I’ve been doing a lot of experiments.
While I don’t manage to make the sub crawl work for me, because I don’t know how to “check for doneness” by ear, I have been taking REW readings on a lot of configurations. And that prompted me to reorient my hifi set and completely reorganize my living room, resulting in better sound even from my mains.
I have found this to be true:
Of course, the final caveat is key: once you find locations that sound good, you will ideally place your Subs in those spots. But you have to keep an open mind to where the room acoustics tell you will be good placements and not what you want aesthetically.
After the reorientation, Denon AVR / Audyssey MultiEQ still do *not* do a good job of taming LF room modes, but anyhow the modes are less severe; nothing *jumps* at you as it did in my previous listening position.
Audyssey is doing a great job of setting the level for the REL sub. You could calibrate the sub that way more reliably than by ear, which seems to lead easily to a timid setting of the sub gain.
E.g. in one test I was getting the sub attenuated 9dB by the AVR. So I took REW readings, set the attenuation on the AVR to 0dB, and turned down the gain knob on the sub until I matched the previous response curve.
REL are honest. For the T/5x, the spec says -6dB at 32 Hz. While I don’t have precise measurement gear, that meshes with my experience.
That seems to be normal with an 8” driver in a sealed box. For comparison, the Kef Kube 8b specifies 34 to 140Hz (-6dB) … btw the Kef 8b is quite a bit cheaper than the REL T/5x.
My mains got nearly as low though, so the sub has not given me much *extension*. But having the sub with its placement flexibility, and bass management with a 80hz crossover, are resulting in better bass than just the mains, noticeably.
If I had taken measurements with REW before the purchase, and had had more of a clue, I think I would have gone for a 10” or 12” sub.
Since I’m seeing lots of tips to get two subs to even out room response, I may go for a 10” Kef sometime soon and use the 8” as the “secondary”.
Looking back at my initial message, though:
Is recommending 12-inch SVS’s to people with a small room akin to recommending 4-wheel-drive vehicles with high horsepower to urbanites?
In a way, I think that is a little true. Those 12" boxes, and especially the ported models, are bulky and noticeable.
Many people getting their first sub probably just want "better bass" in general, not necessarily to go down to 14Hz or get 105dB peak at 20Hz.
If I were advising a friend, I would tell them to get a mic + REW first.
I think many many people would be well served by a 10" model. And for people with bookshelf mains rolling down at 60Hz say, an 8" would make a very clear difference.